08-17-2017, 12:31 AM
Rain Detector
This rain detector will give you a heads-up the instant it starts to rain, hopefully giving you time to close windows and bring in possessions. The battery-powered circuit draws virtually no current when the sensor is dry and the current consumption is low when the buzzer is activated so a couple of AA cells will last a long time. Alternately, a molded power supply with a simple voltage regulator to drop the voltage to 3 volts could be used. The circuit is basically a handy flasher circuit that operates well on only 3 volts using ordinary silicon transistors. When the circuit is triggered, the buzzer is pulsed about once per second for a very short time, giving it a "dripping water" sound which seems appropriate. A slower, longer beep may be had by increasing the 1 uF capacitor. The 10 k resistor may be increased for a longer beep time without decreasing the beep rate but at some point the circuit will cease to function properly, depending on the gain of the transistors.
Rain Detector With Alarm Circuit Mini Project
Today we are going to make a project which will detect the preset water level and when water is reached to this level it will generate a sound.
Objective:
The objective of Water Level Alarm Circuit is to generate a sound with the help of buzzer when a water level in a tank reached to its preset level (Predefined mark).
Components Required:
Following are the required components for making water level alarm circuit:
IC NE555 (Timer IC)
Resistors: R1 = 1K; R2 = 100K;
Capacitor: C1 = 2.2uF (15V)
Buzzer
3V DC battery
Description Of Water Level Indicator:
Here is the simple water level alarm circuit using 555 timer IC which will produce an audible sound when the water level reaches to its preset level. This circuit uses 3V DC power supply. Therefore this circuit is quite handy to use.
This circuit of water level alarm is based on the astable multivibrator which is wired around IC1 (NE555). The operating frequency of this astable multivibrator depends upon the values of capacitor C1, resistors R1 and R2 and the resistance across probes at A and B. when there is no water upto the level of probes, because of open circuit astable multivibratoe will not produce any oscillations hence the circuit will not produce sound. When the water reaches to the level of probes, the circuit will be completed and some current flows through the water. Thus astable multivibrator produces oscillations proportional to the values of C, R1, R2 and the resistance across the probes. Now the buzzer will beeps to indicate that the water is reached to its preset level.